In Dar es Salaam, Tanzania, the main residential corridors trigger informal developments by inhabitants that take place through conversion, extension or demolition and erection of new commercial structures. The subject of study that this PhD discusses is the introduction of commercial spaces, which makes way for new businesses that offer employment on the one hand but also foster social and informal economic activities on the other. It looks particularly at the activities that are developed in informal ways in the street, not through formal planning procedures, but through activities that inhabitants develop together in their daily operations. The commercial street is seen then as a manifestation of intuitive knowledge employed by actors in the creation of space. It is also seen as a product of tacit knowledge informally employed to produce desired results on the street level. To reveal these informal design processes, this study employs a design anthropological approach in studying how people who live and work in the city create the streets’ everyday activities. This study is also an inquiry into how these informal design processes can inform formal design processes that can lead to the enhancement of livelihoods in commercial streets in Tanzania. It thus discusses the relevance of bottom-top design approaches that reflect context-sensitive results. Because the bottom-top design approaches are under-analyzed within the context of Tanzania, they render the emerging corridors in the city of Dar es Salaam marginalized. The study has revealed that there are informal design processes employed by various actors, in diverse socio-economic networks in a commercial street environment that hold potentials and challenges for the street’s and neighborhood’s livelihood. It dives into how the interaction of these studied aspects contributes towards livelihood of the street so that it can be a resource for practitioners, policy makers, authorities and other actors in creating functional urban corridors thereby complementing the top-bottom approach.